• Click on an title to see the short abstract
• Click on a presenter's name in the abstract display to send email
• Only the short, half-page abstracts are available at this site. Extended, two-page abstracts will be published in October 1997. Copies will be mailed to everyone on our mailing list. If you are not a member and would like a copy, please click here to send an email request. Don't forget to include a mailing address in your message.
• Files containing the short abstracts of all the papers are available from our download page.

1. Mark. J. Lake, B. Bimson, D. Gerssen, S. Nooy, N. Roberts
   School of Human Sciences, Liverpool John Moores University;
   RELATING FOREFOOT STRUCTURE TO DYNAMIC PLANTAR PRESSURE DURING LOCOMOTION.
   
2. Nachiappan Chockalingam and Rajesh E.
   Gait Analysis Laboratory, Central Leather Research Institute, Adyar, Chennai 600 020, India
   EXTERNAL ANKLE TORQUE - A COMFORT PARAMETER FOR FOOTWEAR
   
3. Samuel Lee†, Claude Müller†, Darren Stefanyshyn†, Benno Nigg†, Philippe Freychat‡
   †University of Calgary, Calgary, Canada and ‡Decathlon Footwear, France
   FOREFOOT ABDUCTION AND ITS RELATION TO CHANGES IN FOOT LENGTH
   
4. Erez Morag and Peter R. Cavanagh
   Center for Locomotion Studies, Penn State University, University Park, PA, USA
   CHANGES IN FOOT STRUCTURE AND FUNCTION ACROSS THE ADULT LIFE SPAN  

Session 1: Impact
Session 2: Invited Speaker
Session 3: Insoles and Inserts
Session 4: Methods
Session 5:Clinical Aspects and Injury
Session 6:Sports
Session 7:Pressure Distribution
Session 8:Running and Running Shoes
Session 9: Structure and Function

There is evidence to suggest that individuals with reduced plantar fat pad thickness are at a greater risk of overloading the foot during locomotion. Less is known about the relationship between volumetric characteristics of the plantar fat pads and dynamic loading,particularly in the forefoot. The aim of this research will be to determine the structural and deformational characteristics of the forefoot plantar pad under load using magnetic resonance imaging (MRI) and then relate those results to dynamic plantar pressure profiles recorded during barefoot walking and running. An apparatus has been constructed to allow high resolution imaging of both feet while lightly loaded. Pressure measurements have been recorded using an EMED-SF pressure mat. Load under specific metatarsal heads has been determined by overlaying their relative location, obtained from MRI data, onto individual pressure profiles. Initial data on a small group of subjects indicate poor relationships between peak pressure during locomotion and fat pad volume under each metatarsal head. At present structural data are limited to a single lightly loaded condition on a flat boundary. Further work will hope to include tissue deformational characteristics at a range of loads similar to those experienced during locomotion. Deformation will be restricted and modified with the use of individually contoured insoles similar to those found in footwear.

Footwear for day long wear must absorb shock and should be resilient to avoid leg and back strain. The footwear should also not interfere in our normal foot movements. The dorsiflexion and plantarflexion are the two ranges of movements that occurs at the ankle joint during human gait.The torque during these flexion arises due to the external reaction forces that are generated during heel strike and push off periods. Peak dorsiflexion and plantar flexion torque values are considerably less during normal level walking. However, these peak moment values and their timing are dependent on the footwear bottom components. Viz the outsole and the midsole. Preliminary studies reveal that these torque values are increased considerably with different kinds of footwear. The outsole and midsole materials that are available in varying degree of hardness are incorporated into the footwear to provide cushioning and to attenuate the impact forces at heel strike. However these materials modify the centre of pressure pattern considerably depending on their stiffness and compressive properties. The reported work aimed at measuring the peak dorsiflexion and plantar flexion torque for footwear fabricated specially to cater for comfort in various material combinations. The methodology employed in calculating torque is based on modelling the lower extremity by a link segment model incorporating data from kinetic and kinematic parameters. The torque values thus measured and calculated are reported.

The human foot can be approximated as separate forefoot and rearfoot rigid bodies. However, no 3-D data has been published on dynamic relative motion between these two segments and the associated changes in foot shape. The purpose of this study was to quantify forefoot ab-adduction relative to the rearfoot in vitro, and to determine the relationship between relative forefoot ab-adduction and foot length. Video data was collected from reflective marker triads affixed to the ends of Steinmann pins drilled into the tibia, calcaneus, cuboid, and the first and fifth metatarsal bones. Forefoot ab-adduction relative to the rearfoot and foot length were calculated under two axial tibial loads (200N, 600N) and two input motions (dorsi-plantarflexion, internal-external tibial rotation). Ex-internal tibial rotation always produced relative forefoot ad-abduction, with increasing axial tibial load reducing the range of movement. An increase in medial foot length was associated with increasing relative forefoot abduction. However, the forefoot abducted relative to the rearfoot during plantarflexion for flexible feet, but adducted during plantarflexion for rigid and normal feet. These results suggest that the relative movement between the forefoot and rearfoot in the horizontal plane is dependent on the degree of rigidity of the foot. 

A comprehensive study was conducted to identify changes in foot structure and function of healthy individuals across the adult lifespan. Fifty-five subjects ranging from 20-70 years of age (11 subjects per decade) volunteered to participate in the study. Foot structure was obtained from standardized lateral and dorsi-plantar weight bearing plain radiographs, passive range of motion, and an ultrasound based system for characterizing soft tissue. Foot function was obtained during steady speed walking at 0.78 statures per second from stride parameters, 3D rearfoot joint kinematics, EMG of selected foot muscles, and plantar pressure under five foot regions. Analysis of variance was used to identify structural and functional differences between the five age groups.

The results indicated significantly reduced passive range of motion at the subtalar joint, and a trend towards reduced talocrural range of motion with increasing age. No differences in dynamic range of motion during walking at the two joints were found. We found a non-significant trend towards stiffer soft tissue under the heel and significantly reduced heel peak pressure in the elderly. No differences in peak pressures were found under the midfoot, forefoot and hallux. The elderly walked with a shorter stride length (no differences in walking speed), and significantly increased activation of the tibialis anterior during the first quarter of stance. Surprisingly, no differences (or trends) were found in the height of the medial longitudinal arch (determined from radiographic measurements) between the age groups.